This is a little vague. “Healthy weight” is contingent on height, so the term is, at least, imprecise in this context. I’m guessing your point is that BMI is contingent on build as well as height, which is absolutely true and which the article you linked kind of misses out on.
BMI assumes that people get thinner (or relatively slighter-framed) when they get taller which I believe is generally but not universally true, and it assumes people don’t have a lot of muscle. There’s enough variance in the population that there will be people with builds that do not conform BMI’s assumptions (Schwarzenegger, as a famous example). BMI gets used so frequently not because it is accurate but because it is super, super easy to measure. If the theory works, it’s useful for populations, if not for individuals, because populations shouldn’t see lots more muscular people or major changes in average frame.
It’s possible that changes in average BMI are partly unrelated to more people being dangerously overweight—for example, different ethnicities may have some variance in their builds, and the original design of the BMI scale almost doubtlessly failed to account for this, so changes in ethnic composition could affect BMI without actually being a health problem. But BMI is a nice scapegoat because of its imprecision when dealing with individuals; it really isn’t meant to measure them. If its being used to study populations, it’s useful if potentially misleading. If it’s being used by individual doctors with individual patients, that could be a serious problem.
I’ll admit I’m a bit biased on this whole issue, as I’ve found BMI to be quite inaccurate personally.
This is a little vague. “Healthy weight” is contingent on height, so the term is, at least, imprecise in this context. I’m guessing your point is that BMI is contingent on build as well as height, which is absolutely true and which the article you linked kind of misses out on.
BMI assumes that people get thinner (or relatively slighter-framed) when they get taller which I believe is generally but not universally true, and it assumes people don’t have a lot of muscle. There’s enough variance in the population that there will be people with builds that do not conform BMI’s assumptions (Schwarzenegger, as a famous example). BMI gets used so frequently not because it is accurate but because it is super, super easy to measure. If the theory works, it’s useful for populations, if not for individuals, because populations shouldn’t see lots more muscular people or major changes in average frame.
It’s possible that changes in average BMI are partly unrelated to more people being dangerously overweight—for example, different ethnicities may have some variance in their builds, and the original design of the BMI scale almost doubtlessly failed to account for this, so changes in ethnic composition could affect BMI without actually being a health problem. But BMI is a nice scapegoat because of its imprecision when dealing with individuals; it really isn’t meant to measure them. If its being used to study populations, it’s useful if potentially misleading. If it’s being used by individual doctors with individual patients, that could be a serious problem.
I’ll admit I’m a bit biased on this whole issue, as I’ve found BMI to be quite inaccurate personally.